Assistance Required: Two-Factor Authentication (2FA) Code Not Received - Country Code +84

Question

Dear Microsoft Support Team,

I am writing to request urgent assistance regarding an issue I am experiencing with the two-factor authentication (2FA) process on my Microsoft account.

When attempting to log in, I am required to verify my identity via a security code sent to my phone number. However, I am unable to receive the code, and the system displays an error message. I have attached a screenshot of the exact error for your reference.

For your confirmation, my phone number is registered with the Vietnam country code (+84).

Could you please look into this matter and help me resolve the issue as soon as possible so that I can regain access to my account?

Thank you for your prompt support.

Sincerely,

Nhan

Answer 1

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Hi Tô Nghĩa Nhân 

I truly understand how frustrating and inconvenient it can be to lose access to your tenant, especially when encountering error code 399287. 
Please note that we are not Microsoft support, and this is a user-to-user support forum. Moderators and contributors, including external Microsoft employees, do not have backend access and cannot directly intervene in Microsoft products or features. Our role is limited to providing technical guidance and best practice recommendations based on reported issues, requests, or ideas.

Based on the message you received, this situation indicates that you will need to contact your IT administrator within your organization. They are the only ones who have the required permissions to help you re-register or update your multi-factor authentication methods and restore your access. 

For more detailed information, you may refer to the following guidance: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID |…   

In addition, I would recommend using the Microsoft Authenticator app as your primary MFA method. This is the official recommendation from Microsoft, and it provides stronger and more advanced protection compared to using SMS alone. 

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If there is no other Global Administrator and you are the sole admin for the tenant, the next step is to contact Microsoft Support directly. In this situation, you’ll need to reach out to the Support team by calling the phone number listed under Customer service phone numbers - Microsoft Support.  

An agent will be able to create a ticket for you under the affected tenant and then escalate this ticket to the Data Protection team, who can assist you in regaining access.   

Important Note: You may first encounter an AI assistant before reaching a human agent. Please pay close attention to the questions and respond accurately to be routed correctly. Having your information ready will help speed up the process.  

Alternatively, you can set up a Microsoft 365 Business Basic trial, which gives you the ability to submit a support ticket directly through the Microsoft Admin Center   

Step 1: Create a trial business account: Go to Microsoft 365 Business Plans and Pricing and click Try for free to set up a temporary Microsoft 365 tenant with a trial license.    

Step 2: Use this new account to sign in to the Microsoft 365 Admin Center and submit a support request on behalf of the affected tenant 

Step 3: Click Help & Support  

I sincerely hope this information provides helpful direction and additional insight. 

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Answer 2

Follow these steps to troubleshoot not receiving the 2FA code to a +84 (Vietnam) number and the error shown in your screenshot:

1. Check for blocks or delivery issues
   • Avoid repeatedly requesting new codes; excessive or repetitive requests can cause Microsoft to temporarily block sending verification codes to your number or email.
   • If there is heavy compromised traffic from your region, codes may be delayed or temporarily not delivered. These issues are automatically resolved after some time, so wait and try again later instead of making many attempts.
2. Verify the phone number and type
   • Make sure the phone number in your security info is entered correctly with the +84 country code and the correct local number.
   • VOIP numbers cannot be used to receive verification codes. Ensure the registered number is a mobile phone number, not a VOIP line.
3. Check your phone and SMS settings
   • Confirm that your phone is working correctly and has mobile service.
   • Check whether your phone blocks texts from unknown numbers. If so, change the setting to allow messages from unknown senders, then choose I don't have a code on the sign-in screen to have another code sent.
   • If your SMS inbox is full or your messaging app is malfunctioning, clear storage or troubleshoot the app and try again.
4. Try another verification method
   • If another verification method is configured (alternate email, different phone number, or authenticator), choose Try another verification method or Other verification options on the sign-in page and use that method instead.
   • If the block is tied to SMS, switching to email or another method can allow sign-in.
5. Reduce sign-in blocks
   • If you see messages like “Try another verification method” or similar errors, it may indicate a temporary block due to unusual activity or high volume of requests.
   • Switch networks (for example, from Wi‑Fi to mobile data) and try again.
   • If the problem persists, wait at least 24 hours without repeated attempts; if still blocked, wait longer (up to a week) before trying again.
6. Use the sign-in helper and support options
   • For ongoing sign-in issues, use the sign-in helper tool referenced in the documentation to identify the problem and see available support options.
   • If still unable to receive codes or sign in after following the above steps and waiting out any temporary blocks, go to Contact Microsoft Support, describe the issue (including the error code and timestamp from your screenshot), and select Get Help. If needed, choose Contact Support to be routed to the appropriate support option.

Note: For security reasons, Microsoft support agents cannot send verification codes, password reset links, or directly change security info on the account. If all verification methods are unavailable, it may be necessary to wait until access to the registered phone or email is possible, or to follow the automated recovery/sign-in helper paths.

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References:

• Troubleshoot Microsoft verification code issues
• Common problems with two-step verification for a work or school account
• "We didn't receive a response" error message when you try to sign in by using Azure Multi-Factor Authentication